Introducing ADO+
ADO+ is an evolutionary improvement to Microsoft® ActiveX® Data Objects (ADO) that
provides platform interoperability and scalable data access. Because
Extensible Markup Language (XML) is the format for transmitting
data, any application that can read the XML format can process data.
In the extreme case, the receiving component need not be an ADO+
component at all. It might be a Microsoft Visual Studio®-based solution or any application running on any
platform.
Programmability
With Visual Studio development system version 7.0, you can
program against your objects, not against tables and columns.
ADO+ uses strongly typed programming in which business objects
figure prominently.
For example, consider the following line of code, using
conventional (not strongly typed) programming: IF TotalCost > Table("Customer").Column("AvailableCredit")
In this example, you are programming the ADO tables and
columns.
With strongly typed programming, the same example is much
easier: IF TotalCost > Customer.AvailableCredit
Besides being easier to read, the strongly typed code is easier
to write. Specifically, automatic statement completion is sensitive
to the objects you are programming. In the following example, we are
able to navigate across entities in our data set, and
IntelliSense® technology shows the available
tables related to Customers.

Figure 1. Strongly Typed Programming with
IntelliSense
Additionally typed data sets run faster at execution time because
the application doesn't have to search through ADO collection
objects each time it needs to access a data member.
Working with Data Sets
The centerpiece of any software solution using ADO+ is the data
set. A data set is an in-memory copy of database data. A data set
contains any number of data tables, each of which typically
corresponds to a database table or view. A data set constitutes a
"disconnected" view of the database data. That is, it exists in
memory without an active connection to a database containing the
corresponding tables or views.
At run time, data will be passed from the database to a
middle-tier business object and then down to the user interface. To
accommodate the exchange of data, ADO+ uses an XML-based persistence
and transmission format. That is, to transmit data from one tier to
another, an ADO+ solution expresses the in-memory data (the data
set) as XML and then sends the XML to the other component.
The following illustration shows the major components of an ADO+
solution.

Figure 2. ADO+ Architecture
To make working with data easy in Visual Studio 7.0, there are
many new features. For the hardcore XML developer, Microsoft has
included a rich color-coded XML Designer with statement completion
and tag completion.

Figure 3. Color-Coded XML Designer with Statement
and Tag Completion
For a more graphic view of data, developers can use the design
view of the XML Designer. Simply drag and drop tables from any data
source, including Microsoft SQL Server™ and Oracle databases, from
the Server Explorer to the design surface. You can create data sets
that are made up of data from numerous sources including any XML
file.

Figure 4. ADO+ Data Set Designer
Often you need to add, modify, or delete data while you are
designing your application. With the Data Preview tab, you can not
only add and modify data, but also navigate the relationships of
your data.

Figure 5. Data Preview
The data-binding technologies for Visual Studio 7.0 have been
dramatically improved to take full advantage of ADO+. So building
user interfaces that interact with data is easy. More importantly,
now you can bind values to business objects and Web Services.
Last Updated: 7/11/00
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